Laundering method and composition therefor



United States Patent M LAUNDERING METHOD AND COMPOSITION THEREFOR HugoJ. Kaulimann and Alfred P. Mentecki, Bnlfalo, Samuel S. Naistat, Snyder,and Hugo J. Wehrfritz, Lancaster, N.Y., assignors to Food Machinery andChemical Corporation, San Jose, Calif.

No Drawing. Filed Oct. 2, 1956, Ser. No. 613,385

2 Claims. (Cl. 252-99) The present invention relates to an improvedmethod of laundering and to a shelf stable laundering compositiontherefor.

The type of detergent presently employed in laundering consists almostuniversally of the so-called synthetic detergent type wherein the mainsurface active agent is an alkyl aryl sulfonate.

Almost without exception, the synthetic type of laundering powder orliquid contains additional water softeners and so-called builders,carboxy methyl cellulose, all of which aid in controlling the foamingqualities of the product, in controlling the removal of soil from thegoods to be laundered, and in preventing redeposition of the soiluniformly on the goods once the soil is removed therefrom.

Attempts have been made to incorporate bleaching material or agents inthe laundering bath, either as a separate ingredient or as an ingredientintegral with the detergent composition. In general, substantially allknown active bleaching agents have been employed as adjuncts with thesynthetic detergents. These attempts have not been too successful. Thisfailure is generally due to the fact that the normal class of bleachingagents are either not too stable with time, and tend to decompose, asfor instance the hypochlorites, or are not particularly eifective undernormal laundering conditions, as for instance the perborates.

It is an object of the present invention to provide a method oflaundering fabrics and goods under conditions where the solubleperborates may be effectively employed as bleaching adjuncts withsynthetic detergents.

It is another object of the invention to provide a synthetic detergentlaundering composition which is shelf stable, that is, retains itsbleaching activity with time.

In accordance with the broad concepts of the present invention, theusual synthetic detergent is compounded with soluble perborate,preferably sodium perborate, in any suitable amount. In general, theamount of sodium perborate compounded with the detergent will be fromabout 5 to about 30% by weight. In the use of a formulation of this typeat usual laundering temperatures, that is, temperatures from about 100F. to 140 F. more or less, the sodium perborate releases its activeoxygen for bleaching purposes at a rate slower than the usual launderingtime, and therefore, in accordance with the present invention, acatalyst is introduced for speeding up this particular reaction. Thecatalyst is present in extremely small amounts in the final launderingsolution and may be present and effective in quantities so little as0.25 to 5 parts per million of solution.

Under these circumstances, at the normal laundering temperaturesemployed and specified above, the sodium perborate, under the influenceof the catalyst, decomposes and provides eifective bleaching action forthe purpose of whitening white goods, brightening colored goods, andremoving the usual stains encountered in laundering operations such asvegetable juice, ink,

2,975,139 Patented Mar. 14, 1961 ICC chlorophyl (grass stains),chocolate, coffee, tea, and lipstick.

The catalyst preferred for accelerating the decomposition of the sodiumperborate and liberating the active oxygen therefrom is acopper-containing soluble salt and is useful by reason of the fact thatit may be used in such small quantities and any deposition of copperupon the goods is so slight as not to be subsequently noticeable.

A typical formulation of a detergent composition of the presentinvention would include:

Parts by weight Alkyl aryl sulfonate 140 Sodium tripolyphosphate 140Tetrasodium pyrophosphate 60 Carboxymethyl cellulose (CMC) 4 Sodiummetasilicate 22.8 Sodium perborate tetrahydrate 64 Copper sulfatepentahydrate 2.84

The above formulation, when used in the proportion of 1 cupful (34 ozs.)per 10 to 18 gallons of water (the normal capacity of a usual domesticwasher) will provide, at the latter volume, per million parts of washsolution, approximately 40 parts of active oxygen by weight, a quantitysufiicient to produce a good bleaching action on six to eight pounds ofgoods, the capacity of the average Washing load. In general the amountof perborate should be sufficient to furnish 20 to 60 parts per millionof bath.

The detergent formula alone, without perborate, when used to prepare alaundering solution, produced on ordinary bleached sheeting whenlaundered at 140 F., a white having a reflectance of 80.4, as determinedby a Hunter reflectometer. The same sheeting, when laundered under thesame conditions of temperature, time, and the same amount of detergent,plus the addition of the quantity of the perborate specified above,approximately 14.5% based on the total weight of detergent, produced alaundered sheet having a reflectance of 83.5.

An additional piece of the same goods laundered under the sameconditions of temperature, time, and the same amount of detergent, butcontained in addition to the perborate specified, approximately 7% byweight copper sulfate pentahydrate, produced a white of 84.7.

At lower laundering temperature, the effect of the perborate is lesspronounced and the effect of perborate with catalyst is more pronouncedand the action is of especial value in the completion of laundering andstain removal.

Another sample of soiled goods made of unbleached broadcloth waslaundered with a laundering formula similar to that given above, at alaundering temperature of F., a temperature more nearly identical withthat existent in a normal domestic laundering process. The reflectanceof the goods initially employed was 67.8 as determined on the Hunterrefiectometer. The goods, after being subjected to this launderingprocedure with a standard laundering detergent, possessed a reflectanceof 69.7.

Another sample of the same soiled broadcloth was laundered at 120 F.with the same laundering composition, to which was added about 15%sodium perborate tetrahydrate equivalent to 40 parts active oxygen inthe wash solution. There was only a slight increase in brightness of thegoods and the active oxygen content of the laundering solution wassubstantially the same at the end of the laundering operation as at thebeginning thereof. Thus the active oxygen content was 41.6 parts permillion of solution at the start of the laundering procedure and haddropped to only 39.2 after one hour. The reflectance of the launderedgoods was 72.3.

Another sample of the soiled broadcloth was laundered at 120 C. with thedetergent-perborate composition to which was added sufiicient solublecopper salt, that is copper sulfate, to produce in the launderingsolution 1 part dissolved copper per million parts of solution. At thebeginning of the laundering operation the active oxygen content was 34.4parts per million which, after one hour, had dropped to 22.4 parts permillion. The goods after washing and rinsing in the usual way, and ashad been done in the previous operations, possessed a reflectance of77.3. With two parts per million of copper at 120 F. in another batch onthe same goods, the active oxygen content dropped to 8.8 parts permillion from an initial concentration of 22.4 parts per million.

In general, a lower laundering temperature tolerates a greater amount ofdissolved copper. In general, the copper content should be from about Apart per million to not more than 10 parts per million, with a preferredconcentration of from 2 to 4 parts per million, a concentration bestadapted for use in domestic laundering procedures.

It has been found, in accordance with the present invention, that eventhough copper contamination is thought of as a vigorous catalyst ofdecomposition for persalts, such as sodium perborate, dry mixes ofsynthetic detergents of the alkyl aryl sulfonate type and containingfrom 5 to 40% of sodium perborate tetrahydrate are not readilydecomposed on storage, and intimate admixtures may contain thedetergent, the bleachant-namely a water soluble perborateand a watersoluble copper salt and possess excellent shelf stability.

A composition containing 400 parts of the usual type of detergent, 64parts sodium perborate tetrahydrate and 2.84 parts copper sulfatepentahydrate, possessed an active oxygen content initially equivalent to1.42% as determined by titration with permanganate. After standing sixmonths at an average temperature of approximately 25 C., the activeoxygen content was determined as 1.37%, a figure within the experimentalerror of the determination.

It will be understood that although sodium perborate has beenillustrated as the perborate to be employed by reason of itsavailability, any water soluble perborate may be employed in the samefashion as the brightening additive or bleachant for the detergentcomposition.

It will be further understood that although copper sulfate has beenillustrated as the catalytic source, any soluble copper salt will serve,as for instance highly soluble salts such as the nitrate or acetate orslightly soluble salts such as the phosphate, among others. In any case,the dissolved copper compound is the catalyst and the salt chosen shouldprovide a copper concentration in the laundering solution of from about0.5 to parts per million.

Although it has been indicated that the tetrahydrate of sodium perborateis incorporated, it will be understood that other perborates may beemployed, the

amounts of which added to the detergent composition being an amountsutficient to produce 0.8% to about 2.4% active oxygen.

In the example given above, a compound detergent and oxidant of 4 oz. ofsuch composition in 15 gallons of water will produce a concentration ofcopper of approximately 3 parts per million of the laundering solution,while the soluble copper salt should be present in dry mix in an amountsufficient to produce from 0.04% to 0.4% copper.

What is claimed is:

1. A stable dry-mixed detergent composition comprising, an alkyl arylsulfonate synthetic detergent, a water-soluble perborate, and awater-soluble inorganic copper salt, wherein all the components of saidcomposition are admixed and in intimate contact with each other, theperborate being present in an amount sufficient to produce an activeoxygen content in the range of 0.8% to 2.4% by weight, and the inorganiccopper salt being present in an amount sufficient to produce a coppercontent within the range of 0.04% to 0.4% by weight and beingsubstantially free of surface coatings.

2. A method of laundering which comprises heating the goods to belaundered in an aqueous bath at a temperature between about F. to F.until the laundering is completed, said aqueous bath containing an alkylaryl sulfonate synthetic detergent, a watersoluble perborate, and awater-soluble inorganic copper salt, the amount of perborate beingsufficient to produce an active oxygen content in the composition offrom 0.8% to 2.4% by weight, the amount of copper salt being sufiicientto produce a copper concentration in the range of 0.5 part per millionto 10 parts per million by weight of the laundering solution, andwherein said synthetic detergent, said water-soluble perborate, and saidwater-soluble inorganic copper salt are introduced into said aqueousbath in the form of a dry-mixed composition wherein all the componentsof said composition are admixed and in intimate contact with each other,and said inorganic copper salt being substantially free of surfacecoatings.

References Cited in the file of this patent UNITED STATES PATENTS2,477,631 Levy et a1 Aug. 2, 1949 2,498,344 Rider et a1 Feb. 21, 19502,576,205 Apperson Nov. 27, 1951 2,706,178 Young Apr. 12, 1955 2,763,618Hendrix Sept. 18, 1956 FOREIGN PATENTS 188,811 Great Britain Nov. 23,1922 291,743 Great Britain Sept. 30, 1929 310,030 Great Britain June 5,1930 OTHER REFERENCES Dahlstrom: Chemical Abstracts, vol. 20, pp. 3087,3088 (1926).

1. A STABLE DRY-MIXED DETERGENT COMPOSITION COMPRISING, AN ALKYL ARYLSULFONATE SYNTHETIC DETERGENT, A WATER-SOLUBLE PERBORATE, AND AWATER-SOLUBLE INORGANIC COPPER SALT, WHEREIN ALL THE COMPONENTS OF SAIDCOMPOSITION ARE ADMIXED AND IN INTIMATE CONTACT WITH EACH OTHER, THEPREBORATE BEING PRESENT IN AN AMOUNT SUFFICIENT TO PRODUCE AN ACTIVEOXYGEN CONTENT IN THE RANGE OF 0.8% TO 2.4% BY WEIGHT, AND THE INORGANICCOPPER SALT BEING PRESENT IN AN AMOUNT SUFFICIENT TO PRODUCE A COPPERCONTENT WITHIN THE RANGE OF 0.04% TO 0.4% BY WEIGHT AND BEINGSUBSTANTIALLY FREE OF SURFACE COATING.